60Hz motor at 50Hz again....

[foretmark]

I know much has come up about this, but I haven't seen any answer to the question of, if I'm going to put a 60Hz motor into service with a 50Hz supply, in order to get the V/Hz ratio down by reducing the voltage...is there any 'voltage divider' way of doing it...in other words, without a VFD or additional transformer other costly device?

208-230v 3ph 60Hz cont. duty SF 1.15...used to directly drive a pump. (going into 220v 50Hz service)

The reduced speed I'm not so worried about, it's the heating and potential motor failure. The thing will not be running continuously, however, it is possible that it will be running frequently enough to cause problems.

 

[dpc]

An autotransformer will be the best option for a small voltage change. Because the voltage difference is small, the autotransformer will be small.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[foretmark]

the motor FLA would be around 8A....wouldn't I need about a 2kva transformer? That's a monster relative to our equipment....

 

[djs]

You would need to drop about 30 volts per phase. So autotransformer KVA would be 30 * 8 *3 = 720 VA!

 

[dpc]

That's the beauty of autotransformer connection in this application. The transformer rating is a function of the voltage buck/boost required.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[foretmark]

Thanks DPC...good info...

 

[waross]

Hi dpc;
I have used the open delta autotransformer connection many times.
Each transformer will carry full motor current plus transformer current, approximately 1 amp for a total of 9 amps. 9 x 28.3 = 255 VA. for short time duty you may get away with 250 VA. Use two single phase transformers. (Open delta)


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[starkopete]

Here's an oldie but goody.